I found a strange space between the Identity icon* and the URL text of the address bar. It was about an inch wide.
* Usually appears as a lock, sometimes expands to show the identity name, coloring in red or green depending on validation status.
This occurs on computers with a finger print reader hardware installed.
Firefox picks up the finger print authentication plugin (which however is not used by any Firefox built-in feature, though I'm not sure about Master Password), but it sets all plugins to "Ask to Activate" by default.
This causes the fingerprint reader plugin to remain disabled at start-up, causing the weird bug.
To solve the problem in Firefox 30.0:
- Click Menu (three stacked bars) > Add-ons.
- Click Plugins on the left side of Add-ons Manager.
- Find the plugin related to your fingerprint reader.
- Most likely it is "TrueSuite" or "SimplePass"
- You can look at about:plugins to help find the exact plugin name. Look for keywords like fingerprint, finger, authentication, pass, etc.
- For more information, check here.